Jesper,
I have a circuit which is rather different then any I'm aware off, although the Healey-Driscoll circuitry I guess could be said to be its closest relation, its based on what is commonly called an Emitter coupled XO (that is the resonator circuit is in the Emitter of the transistor).
The primary propose of the circuit is lowest close in PN, rather then as a Frequency standard...
I have troubles with measuring close-in Phase noise at ~100MHz (The Timepod is limited to 50MHz) - and with the HP E5500 system I need XO's with AFC function, so I'm adding AFC to the next PCB spin which is actually quite simple with the circuit topology.
The close-in in Phase noise is approaching the thermal noise of 100 ohm resistor (so carrier power is your friend here), this can be reduced but at this level, the XO is no longer the systems limiting factor... although its now of academic interest to see how much further it can be improved.
Last measurements made (please bare in mind the system limitations) where below 130dBc at 10Hz (90.316MHz).
I'm tidying up the design and with the AFC function expect to get "real" performance figures.
Its a question of time that I dont have ATM as the circuit already exceeds performance requirements for the current design project...
A link to to the 1974 Healey / Driscoll Patent:-
LOW NOISE VHF CRYSTAL HARMONIC OSCILLATOR
I have a circuit which is rather different then any I'm aware off, although the Healey-Driscoll circuitry I guess could be said to be its closest relation, its based on what is commonly called an Emitter coupled XO (that is the resonator circuit is in the Emitter of the transistor).
The primary propose of the circuit is lowest close in PN, rather then as a Frequency standard...
I have troubles with measuring close-in Phase noise at ~100MHz (The Timepod is limited to 50MHz) - and with the HP E5500 system I need XO's with AFC function, so I'm adding AFC to the next PCB spin which is actually quite simple with the circuit topology.
The close-in in Phase noise is approaching the thermal noise of 100 ohm resistor (so carrier power is your friend here), this can be reduced but at this level, the XO is no longer the systems limiting factor... although its now of academic interest to see how much further it can be improved.
Last measurements made (please bare in mind the system limitations) where below 130dBc at 10Hz (90.316MHz).
I'm tidying up the design and with the AFC function expect to get "real" performance figures.
Its a question of time that I dont have ATM as the circuit already exceeds performance requirements for the current design project...
A link to to the 1974 Healey / Driscoll Patent:-
LOW NOISE VHF CRYSTAL HARMONIC OSCILLATOR
Hello,
please excuse me for the naive question, but 200 pages are a lot to read, and I got lost among all the different versions tested
According with your findings, which is the better performing solution for oscillator frequencies of 45 and 49 MHz? I am referring to noise and jitter measurements, not listening impressions.
Many thanks for the patience.
please excuse me for the naive question, but 200 pages are a lot to read, and I got lost among all the different versions tested
According with your findings, which is the better performing solution for oscillator frequencies of 45 and 49 MHz? I am referring to noise and jitter measurements, not listening impressions.
Many thanks for the patience.
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@JohnW: Thanks John for linking to the Healey/Driscoll patent and sharing your measurement results.
Quite impressive reaching 130 dBc for a 90.316 MHz AT-cut crystal (I reckon that in practice it would translate to something like ~ 145 dBc for a 11.2 MHz crystal ... ?) ... Should you feel fine with sharing any further results along the way I'd be interested in seeing them ...
... the "only" ATMs I know of are the ones obligedly supplying me with money on travels ... can I ask you what ATM is acronym for?
@nicpom: I am not sure there have been any conclusive measurements of the various oscillator types in the thread (to my memory that is). However, for the AT cut I believe Andrea finds the Driscoll to be the most interesting approach whereas Herbert Rutgers, who designed the oscillator mentioned in the first posts, would prefer the Colpitts-Clapp (as I understand it).
Cheers,
Jesper
Quite impressive reaching 130 dBc for a 90.316 MHz AT-cut crystal (I reckon that in practice it would translate to something like ~ 145 dBc for a 11.2 MHz crystal ... ?) ... Should you feel fine with sharing any further results along the way I'd be interested in seeing them ...
... smiling here
... the "only" ATMs I know of are the ones obligedly supplying me with money on travels ... can I ask you what ATM is acronym for?@nicpom: I am not sure there have been any conclusive measurements of the various oscillator types in the thread (to my memory that is). However, for the AT cut I believe Andrea finds the Driscoll to be the most interesting approach whereas Herbert Rutgers, who designed the oscillator mentioned in the first posts, would prefer the Colpitts-Clapp (as I understand it).
Cheers,
Jesper
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Many thanks. So AT cut, and two possible circuits. And, second naive question, is it still possible to buy them? I know that some GB were launched, but is time expired or something is still available?
Yes! New finished boards for the big crystals please!
I have been so unlucky with my oven builds, I did not get them to work properly.
And my second SC-cut oscillator is also not working
How much will cost oven oscillator with 45.1584 crystal, bare boads + crystal & finished board + crystal?
I have to check the exact frequency on the 30meg cristal, i just know they are very hgh qualty.I also have exactly 50.00000 and 64.000000mhz cristals.
The oven must still be tested (measure) to confirm its effectiveness, it’s the chef’s surprise.
Hi,
I had the chance to compare three clocks today:
-crystek cchd 957
-accusilicon as318-b-451584
-Andrea Mori sc-cut, driscoll pcb without oven.
All 45mhz samples.
The Andrea Mori clock is the best sounding by far; it delivers lots of openness, air, focus and a warm tone without any harshness.
The accusilicon was second best and at quite a distance from the Andrea Mori clock. There was more harshness, less dynamic and a bit fatuiging in comparison.
The crystek is a bit behind the accusilicon with a tad more harshness and similar overall sound.
All clocks were used on an Ian Canada fifopi, battery/supercap powered and bypassed ldo’s, mounted on an Allo Usbridge Sig, feeding my, tuned to the max, 4 deck dddac.
I have been living happily for quite some years with the crystek clocks but now after using the Andrea Mori clock for about a year I cannot imagine going back to this type of clock anymore. The music is so much more natural and “analog”. You have to hear the difference to understand how much there is to gain with good clock design.
I cannot wait to try the new driscoll design clock with the 5mhz chrystals. These promise to be even better!
Regards
I had the chance to compare three clocks today:
-crystek cchd 957
-accusilicon as318-b-451584
-Andrea Mori sc-cut, driscoll pcb without oven.
All 45mhz samples.
The Andrea Mori clock is the best sounding by far; it delivers lots of openness, air, focus and a warm tone without any harshness.
The accusilicon was second best and at quite a distance from the Andrea Mori clock. There was more harshness, less dynamic and a bit fatuiging in comparison.
The crystek is a bit behind the accusilicon with a tad more harshness and similar overall sound.
All clocks were used on an Ian Canada fifopi, battery/supercap powered and bypassed ldo’s, mounted on an Allo Usbridge Sig, feeding my, tuned to the max, 4 deck dddac.
I have been living happily for quite some years with the crystek clocks but now after using the Andrea Mori clock for about a year I cannot imagine going back to this type of clock anymore. The music is so much more natural and “analog”. You have to hear the difference to understand how much there is to gain with good clock design.
I cannot wait to try the new driscoll design clock with the 5mhz chrystals. These promise to be even better!
Regards
- TWTMC-AIO:
Good morning Andrea,
having a TWTMC-AIO with SC Cut crystals in my drawer and would like to use it with my FIFOPI. I know, it need 9 to 12 V but I do not know the current needed. Would be great to know if i could use an existing small transformer for that or get a bigger one.
BR
Ernst
Good morning Andrea,
having a TWTMC-AIO with SC Cut crystals in my drawer and would like to use it with my FIFOPI. I know, it need 9 to 12 V but I do not know the current needed. Would be great to know if i could use an existing small transformer for that or get a bigger one.
BR
Ernst
Good point, but I strangly haven't bought a lab psu throughout all the years.
And, still good point, I do have a good clamp meter and can borrow a 9V psu from other thingie and test the current w/o a resistor.
Great, thanks
Ernst
Just use the dil pcb from Andrea. You can connect with u-fl, sma or directly. I used u-fl first but directly is a bit better. See attached pictures.
It will be a problem fitting two of these dil pcb’s though. But Andrea is designing new boards to fit the fifopi; I think using the clocks on fifopi is the most used implementation of the clocks.
Regards,
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